Question about FAL and AR primer dimpling...

C

Charmedlyfe

Moderator
My FAL had a 1-piece firing pin. I noticed a tendency for it to dimple primers when the bolt was released and a round chambered. I noticed this on rounds ejected but not fired. It is a noticable dimple. I replaced the firing pin spring a couple times, with no sucess. I then got a 2-piece firing pin from DSA and the problem went away.

I posted this on FNFAL.com, and a guy gave me a line about this being normal for FALs and ARs. My AR doesn't dimple primers. My concern was that this might result in an ND. Is this guy right and I'm just paranoid? Consider this a solicitation of opinions.....
 
It actually wasn't a line. He was telling you the truth.

There have been quite a few military semi-auto rifles, including the M-16/AR guns, the M 1 Garand, the SKS, and others, to do this because they don't have a firing pin spring, or the spring isn't powerful enough (by design) to keep the firing pin from contacting the primer of the round being loaded.

When the action slams home the firing pin pops forward and dimples the primer, but it's not normally enough to set it off unless the primer is extremely sensitive.

I've been shooting commercial and military ammo in my SKS for quite a few years, and nothing has ever happened even though I've had lots of dimpled primers.

There HAVE, however, been reports of slam fires on some of these guns. One factor that seems to be present in a lot of cases is the use of one of the super-slick wonder lubricants on the firing pin. Apparently these lubes reduce friction just enough that a slam fire becomes possible.

I use a very light coating of a medium-bodied grease on the firing pin in my SKS, and it has actually cut down on the dimpling problem.

The possible reason for this to quit with a firing pin replacement in your FAL is either the 2-piece pin is lighter (and thus don't develop enough momentum to dimple the primer) or there's enough friction between the parts that they don't get enough velocity to dimple the primers.
 
It is lighter---less free mass moving. Also, I think the pin is a little shorter. Anyway, the new pin is an added margin of safety. I don't see where people should become hostile over that....or maybe I'm just being sensitive.
 
George,
I don’t own an FAL so I don’t know if it’s normal for them but having a spring on the firing pin like you say I would think it’s not. Now with AR’s and AK’s it’s very common, as a matter of fact I have never owned one that didn’t dimple primers if they were soft. The firing pin on AR’s and AK’s are free floating, the inertia generated when the bolt closes causes the firing pin to dimple soft and sometimes hard primers in both gun’s, I have also seen this in my DR200 and I think my Mini-14 did the same. If you don’t keep them clean or reload with soft primers it can cause Slam Fires. With any semi-auto rifle that does not have a firing pin spring or something to keep the firing pin back when the bolt closes the dimples are possible (likely) and that’s one reason military primers are so hard. I personally have never had one slam fire but it’s possible.

John
 
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